Discrimination of closely resembling PEC targets based on natural resonant frequencies

The Natural Resonant Frequencies (NRFs) obtained from the late time response of targets are aspect independent in nature and thus, is well suited for radar target identification. In resonance based identification techniques, the accurate determination of NRFs is very important. In this paper, a technique for identifying the true NRFs of objects, useful in discriminating two closely resembling objects is proposed. The NRFs are extracted from the E-field response of the object using the Vector Fitting (VF) method. The NRFs of database object and the Radar Cross Section (RCS) of unknown object are used to discriminate between them. A risk factor is defined as a measure of discrimination. In this study, ellipsoids with different axial ratios are considered for discrimination and the results are presented.